Hard disc devices have been used in apparatuses performing information processing such as computers. Such hard disc devices have been used as external devices of computers, but are recently also mounted on home electric appliances, such as televisions and video recorders, and electronic devices for automobiles,
A conventional hard disc device 200 illustrated in FIG. 14 houses a driving mechanism in a casing body 201. The driving mechanism includes hard discs 202 serving as recording media, a spindle 203 (this spindle is rotated by a motor, which is not illustrated) that rotates the hard discs 202, magnetic heads 204 that record information on and read out information from the hard discs 202, a carriage 205 that supports the magnetic heads 204 and turns above surfaces of the hard discs 202, a voice coil motor (VCM) 206 that causes the carriage 205 to turn precisely to control the magnetic head 204 to perform scanning, and a pivot shaft 207 that is fixed to the casing body 201 and is coupled to the carriage 205, The pivot shaft 207 has an approximately columnar shape, for example, and has a structure of a bearing.
The carriage 205 turns above the surfaces of the hard discs 202 with the center of the pivot shaft 207 as the center axis. For the fastening between the carriage 205 and the pivot shaft 207, a tolerance ring is used, for example. The fastening of the carriage 205 to the pivot shaft 207 prevents motive power of the VCM 206 for turning the carriage 205 from propagating to the casing body 201.
The tolerance ring has a ring shape formed from a platy member by being approximately circled along a predetermined direction. After the tolerance ring is inserted into an opening of the carriage 205, the pivot shaft 207 is pressingly fitted in the inside of the tolerance ring. As for such a tolerance ring, a tolerance ring having raised contact surfaces in a convex shape is disclosed (e.g., refer to Patent Literatures 1 and 2). A tolerance ring having an outer periphery in a corrugation shape is also disclosed (e.g., refer to Patent Literatures 3 and 4). In the tolerance rings described in Patent Literatures 1 to 4, the fastening between the carriage 205 and the pivot shaft 207 is made by pressingly making the raised contact surfaces or the projecting portions in the corrugation shape contact with a side surface of either the carriage 205 or the pivot shaft 207.